Method for conducting well testing operations with nitrogen lifting, production logging, and buildup testing on single coiled tubing run

ABSTRACT

A method for performing a pressure buildup test in an evaluation zone of a well includes the steps of perforating the well in the evaluation zone to allow the flow of hydrocarbon fluids from the reservoir, deploying a pressure buildup test system into the evaluation zone, supplying the lift fluid via the coiled tubing to lift the hydrostatic pressure to lift the hydrocarbon fluids from the evaluation zone toward the surface, moving the packer to the set position, monitoring the pressure data in the evaluation zone, closing the shut-in valve when the stable state of the pressure data is reached, and measuring a buildup pressure in the evaluation zone using the pressure monitoring device. The pressure buildup test system includes a packer, a sub port, a coiled tubing, a shut-in valve, a pressure monitoring device, and a PLT.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application No. 62/131,273 filed on Mar. 11, 2015. For purposes of United States patent practice, this application incorporates the contents of the Provisional Application by reference in its entirety.

TECHNICAL FIELD

Described are methods and apparatus for performing pressure buildup testing in a well. More specifically, provided are methods and apparatus for performing pressure buildup testing in a well using a nitrogen lift.

BACKGROUND

Currently three coiled tubing runs are required to perform one well test operation during the exploration phase. The first coiled tubing run is to run coiled tubing into the wellbore to lift the well with nitrogen (N₂) prior to installing pressure gauges on the wireline. The second coiled tubing (“CT”) run again lifts the well with N₂ just before the well shut-in period for the pressure buildup test. The third coiled tubing run is for the purpose of pumping a heavy kill fluid into the well after the well test operation is complete.

Coiled tubing insertions are generally required for the purpose of evaluating unconventional and tight gas zones. Unconventional and tight gas zones are typically quite deep so, if there is heavy fluid in the well, they do not flow unless the hydrostatic pressure is “lifted” by pumping nitrogen into the well. With a lower hydrostatic pressure, the zones can flow and the flow can be measured and tested.

When a zone of interest is found, it is required to do a pressure buildup test. The current practice is to lift a zone of interest with nitrogen, then stop to pull the coiled tubing out of the well to deploy pressure gauges and the shut-in valve into the well, then run coiled tubing to lift the well again to apply the drawdown needed for the pressure buildup test, then at the conclusion of the test the gauges must be retrieved from the well. Important pressure data is lost between the well's flowing state and the time when pressure gauges are installed up to 24 hours later. A technical solution is needed to allow for the recording of the early pressure buildup data of the zone to better understand the reservoir quality.

Zones of interest in unconventional and tight gas zones generally require nitrogen lifting before they can be logged and evaluated. Currently, when a zone of interest is identified in a well, the buildup test equipment has to be run downhole separately after a coiled tubing run to lift the well with nitrogen. The buildup test equipment includes pressure gauges and a shut-in tool run by slickline to the surface. The well needs to be lifted for a second time after installing gauges and a shut-in (SI) tool on the slickline. The pressure gauges record pressure over time. The SI tool closes after a set period of time expires allowing the pressure in the well to build up. The SI can be activated on a timer or from the surface. The pressure gauges then record the pressure buildup. The buildup rate can be used to evaluate the productivity of a zone of interest.

SUMMARY

Described are methods and apparatus for performing pressure buildup testing in a well. More specifically, provided are methods and apparatus for performing pressure buildup testing in a well using multiple well nitrogen lifting steps and zonal isolations of areas of interest in one CT run.

In one aspect, a method for performing a pressure buildup test in an evaluation zone of a well is provided. The method includes the steps of perforating a casing of the well in the evaluation zone, where perforating the casing is operable to allow the flow of hydrocarbon fluids from the reservoir to the evaluation zone, deploying a pressure buildup test system into the evaluation zone of the well. The pressure buildup test system is configured to measure pressure in the evaluation zone. The pressure buildup test system includes a packer configured to isolate the evaluation zone when in a set position and configured to create an annulus between the casing of the well and the pressure buildup test system in a retracted position, a sub port configured to deliver a lift fluid to the evaluation zone, a coiled tubing configured to deliver the lift fluid from the surface to the sub port, where the pressure buildup test system is deployed by the coiled tubing. The coiled tubing includes a cable configured to transmit electronic signals to a surface control system from the pressure buildup test system. The pressure buildup test system further includes a shut-in valve configured to control the flow of hydrocarbon fluids from the evaluation zone to a well space at a distance above the packer, a pressure monitoring device configured to measure pressure data in the evaluation zone and transmit the pressure data to the surface control system through the cable, and a PLT configured to measure flow from the evaluation zone through the shut-in valve to the well space above the packer. The method further includes the steps of supplying the lift fluid via the coiled tubing to lift the hydrostatic pressure of the evaluation zone, where lifting the hydrostatic pressure is operable to lift the hydrocarbon fluids in the evaluation zone through the annulus between the packer and the casing toward the surface, moving the packer to the set position, where in the set position the packer contacts the casing of the well such that the hydrocarbon fluids in the evaluation zone flow through the shut-in valve to the well space, monitoring the pressure data of the evaluation zone to determine a stable state of the pressure data, closing the shut-in valve when the stable state of the pressure data is reached to prevent the flow of the hydrocarbon fluids from the evaluation zone, and measuring a buildup pressure in the evaluation zone using the pressure monitoring device.

In certain aspects, the lift fluid is nitrogen. In certain aspects, the method further includes the step of returning the packer to the retracted position after the buildup pressure is measured. In certain aspects, the method further includes the step of re-positioning the pressure buildup test system to a second evaluation zone, moving the packer to the set position, monitoring the pressure data of the hydrocarbon fluids flowing through the shut-in valve to determine the stable state of the pressure data in the second evaluation zone, closing the shut-in valve when the stable state of the pressure data is reached to prevent the flow of the hydrocarbon fluids from the second evaluation zone, and measuring the buildup pressure in the second evaluation zone using the pressure monitoring device. In certain aspects, the method further includes the step of filling the well with a completion fluid. In certain aspects, the completion fluid is brine. In certain aspects, the coiled tubing includes a valve configured to shut-off the flow of the lift fluid. In certain aspects, the method further includes the steps of drilling the well for production of hydrocarbon fluids and preparing the well by installing the casing in the well.

In a second aspect, an apparatus for pressure buildup testing in an evaluation zone of a well is provided. The apparatus includes a packer configured to isolate the evaluation zone when in a set position and configured to create an annulus between a wall of the well and the apparatus in a retracted position, a sub port configured to deliver a lift fluid to the evaluation zone, a coiled tubing configured to deliver the lift fluid from a surface to the sub port, where the apparatus is deployed by the coiled tubing. The coiled tubing includes a cable configured to transmit electronic signals to a surface control system from the apparatus. The apparatus further includes a shut-in valve configured to control the flow of hydrocarbon fluids from the evaluation zone to a well space at a distance above the packer, a pressure monitoring device configured to measure pressure data in the evaluation zone and transmit the pressure data to the surface control system through the cable, and a PLT configured to measure flow from the evaluation zone through the shut-in valve to the well space above the packer.

In certain aspects, the surface control system is configured to send and receive electronic signals to the shut-in valve. In certain aspects, the surface control system is configured to send and receive electronic signals to the pressure monitoring device. In certain aspects, the surface control system is configured to send and receive electronic signals to the PLT. In certain aspects, the surface control system is configured to display the electronic signals transmitted by the cable and is further configured to store the electronic signals transmitted by the cable.

In a third aspect, a method for performing a pressure buildup test is provided. The method includes drilling a well for production of hydrocarbons and preparing the well by casing the well. A coiled tubing is then inserted into the well. Nitrogen is supplied via the coiled tubing to lift the hydrostatic pressure of the evaluation zone. The pressure of the evaluation zone is also measured using at least one pressure monitoring device.

In another aspect, an apparatus for pressure buildup testing in a well is provided. The apparatus includes at least one downhole pressure monitoring device operable to detect pressure in an evaluation zone. The apparatus further includes a packer for isolating a zone of interest. The apparatus also includes at least one data transmission device in communication with the at least one downhole pressure monitoring device for transmitting data to a surface of a well. The apparatus further includes a coiled tubing operable to allow the flow of nitrogen, as well as a valve for controlling the flow of nitrogen through the coiled tubing. The apparatus also includes a production logging tool for measuring and characterizing hydrocarbon flow.

DESCRIPTION OF DRAWINGS

These and other features, aspects, and advantages will become better understood with regard to the following descriptions, claims, and accompanying drawings. It is to be noted, however, that the drawings illustrate only several embodiments and are therefore not to be considered limiting of the inventive scope as it can admit to other equally effective embodiments.

FIG. 1 shows a plan view of the pressure buildup test system in accordance with an embodiment.

FIG. 1a shows a plan view of the pressure buildup test system in accordance with an embodiment.

FIG. 2 shows a plan view of the pressure buildup test system in accordance with an embodiment.

FIG. 3 shows a plan view of the pressure buildup test system in accordance with an embodiment.

DETAILED DESCRIPTION

Although the following detailed description contains many specific details for purposes of illustration, it is understood that one of ordinary skill in the art will appreciate that many examples, variations and alterations to the following details are within the inventive scope and spirit. Accordingly, the exemplary embodiments described and provided in the appended figures are set forth without any loss of generality, and without imposing limitations, on the scope.

The method and apparatus provided allow a pressure buildup test to be performed in one or more evaluation zones of a zones of interest in a well, using only one coiled tubing run. As used, “zone of interest” refers to a promising zone of a reservoir for hydrocarbon production. “Promising” as used throughout means a zone that is likely or substantially likely to produce hydrocarbon fluids. A zone of interest can be physically defined by the geophysical data recorded by wireline or drilling logs performed as part of the initial preparation of a well, such prior to casing a well. A given well can have multiple zones of interest and a given zone of interest can have multiple evaluation zones.

Advantageously, the methods and apparatus provide more accurate well test data because the nitrogen lifting and well-testing operations are combined into a single apparatus and process.

Referring to FIG. 1, an embodiment of the apparatus of pressure buildup test system 10 is shown. Pressure buildup test system 10 includes coiled tubing 20. Coiled tubing 20 can be any coiled tubing containing cable 22 operable to be inserted into well 80. Cable 22 transmits electronic signals or data from surface 100 to equipment downhole. Cable 22 provides electronic communication with the downhole devices, allowing both sending and receiving of real-time data and information to and from the surface. In at least one embodiment, cable 22 provides the means to actuate downhole devices. Examples of downhole devices include flow control devices, sample devices, perforating tools, packers, downhole recorder devices. Cable 22 can be any data transmission device that allows for communication between surface control system 70 and the downhole devices, alternately cable 22 can be any transmission device that allows for power delivery between surface control system 70 and the downhole devices, and alternately cable 22 can be any transmission device that allows for simultaneous communication and power delivery between surface control system 70 and the downhole devices. Examples of cables that can be used as cable 22 include electrical cable and fiber optic cable. Coiled tubing 20, including cable 22, can be a coiled tubing appropriate for transmission of nitrogen, transmission of fluids into the well, logging and perforating. In at least one embodiment, pressure buildup test system 10 is conveyed into well 80 using an electric line, such as a wireline. In at least one embodiment, well 80 is cased with casing 82. In at least on embodiment, pressure buildup test system 10 and the pressure buildup test employ a single coiled tubing, in a single coil tubing run.

Coiled tubing 20 delivers a lift fluid from surface 100 to sub port 30. The lift fluid provides the “lifting” of the hydrostatic pressure of the hydrocarbon fluid in the well to achieve well initiation. As used here, “well initiation,” refers to when the density of the hydrostatic column in the well is reduced to have a positive pressure drawdown (for example, when the sand face pressure is higher than the hydrostatic bottomhole pressure), such that the hydrocarbon fluid from the formation flows into the well and to the surface. The lifting of the hydrostatic pressure prompts the fluid in well 80 to flow toward surface 100 around coiled tubing 20 in well space 84. The lift fluid is any fluid capable of lifting the hydrocarbon fluid in well 80. In at least one embodiment, the lift fluid is nitrogen. This is also known as nitrogen kick-off. Nitrogen is inert and inexpensive. In at least one embodiment, well initiation is employed using nitrogen fed through coiled tubing 20 from surface 100 to sub port 30. In at least one embodiment, the hydrocarbon fluid is lifted from well 80 in the absence of any mechanical equipment, such as a jet pump. In at least one embodiment, the coiled tubing is in the absence of hydrocarbon fluid flowing within it.

Coiled tubing 20 is connected to surface control system 70. Surface control system 70 includes the equipment necessary to transmit the lift fluid from surface 100 to sub port 30. In at least one embodiment, surface control system 70 includes a blower. In one embodiment, surface control system 70 includes a pump. Surface control system 70 also includes the readout system necessary to display the electronic signals and data transmitted through cable 22 of coiled tubing 20, including, for example, monitors, computer processors, and other control equipment. Surface control system 70 includes equipment known in the art necessary to operate and control the system in well 80.

Referring to FIG. 2, an embodiment is shown, in which well initiation is employed using well initiation pump 120. Well initiation pump 120 connects to surface control system 70 by cable 22. Well initiation pump 120 connects to packer 40, such that well initiation pump 120 is located between surface 100 and packer 40. Well initiation pump 120 provides the motive force to lift the hydrocarbon fluid in well 80. Well initiation with a pump operates under the same principle as well lifting using gas, where the hydrostatic back-pressure of the well is reduced to encourage flow. Well initiation pump 120 can be any type of pump capable of producing a motive force to induce the hydrostatic back-pressure of the well to flow. The selection of pump for well initiation pump 120 can depend on the fluids that are expected to flow and the presence of gases in the fluids. Examples of pumps that can be used as well initiation pump 120 include reciprocating pumps, progressive cavity pumps, electrical submersible pumps, and jet pumps. In at least one embodiment, well initiation pump 120 is an electric submersible pump. In an embodiment with well initiation pump 120, pressure buildup test system 10 is in the absence of sub port 30 and coiled tubing 20.

Referring again to FIG. 1, in some embodiments, sub port 30 connects to packer 40. Packer 40 isolates evaluation zone 90 in well 80. Isolating well 80 at or near the zone of interest can prevent “wellbore storage effects” and thus reduce the risk of corrupted well test data. As used here, “wellbore storage effects” refers to a phenomena that is observed in well testing, Wellbore storage effect occurs when the shut-off test pressure is being measured at the surface, the initial pressure values are not a direct representation of the reservoir data but rather are affected by the wellbore column (in other words, the pressure changes will be cushioned by the wellbore column). In the embodiments described, the wellbore storage effect is minimized or avoided altogether by sealing evaluation zone 90 with packer 40 and measuring pressure data as close as possible to evaluation zone 90. In some embodiments, packer 40 is set above evaluation zone 90. In some embodiments, packer 40 is set below evaluation zone 90. In some embodiments, packer 40 is set in the midst of evaluation zone 90.

Packer 40 has a retracted position and a set position. In the retracted position, as shown in FIG. 1, annulus 50 forms between the walls of well 80 and the outside surface of packer 40 around which hydrocarbon fluid in evaluation zone 90 can flow. In the set position, as shown with reference to FIG. 1 a, packer 40 contacts the walls of well 80 preventing hydrocarbon fluid in evaluation zone 90 from moving around packer 40. In the set position, hydrocarbon fluid can only move from evaluation zone 90 toward surface 100 by passing through shut-in valve 52 to subport 30. Shut-in valve 52 redirects hydrocarbon fluid from evaluation zone 90 to well space 84 between coiled tubing 20 and casing 82 in well 80. In some embodiments, packer 40 is a straddle packer. In some embodiments, packer 40 is a temporary packer.

Cable 22 of coiled tubing 20 connects to shut-in valve 52, pressure monitoring device 54, and PLT 60. In at least one embodiment, shut-in valve 52 is physically connected to packer 40. Shut-in valve 52 is a downhole shut-in valve (DHSI valve). As used herein, a “downhole shut-in valve” refers to a valve designed to close in less than three seconds so that the initial transient pressure behavior can be recorded. Shut-in valve 52 when closed provides a downhole shut-in which minimizes wellbore effects that distort well transient pressure data. In at least one embodiment, as shown in FIG. 1, pressure monitoring device 54 is physically connected to shut-in valve 52, such that shut-in valve 52 is situated between packer 40 and pressure monitoring device 54. In at least one embodiment, as shown with reference to FIG. 3, pressure monitoring device 54 is physically connected to packer 40 adjacent to shut-in valve 52. Pressure monitoring device 54 operates independently from shut-in valve 52. In embodiments where shut-in valve 52 is not used, pressure monitoring device 54 can still be used.

Pressure monitoring device 54 is a pressure gauge to measure and record pressure data. Pressure monitoring device 54 measures the pressure in well 80. In at least one embodiment, pressure monitoring device 54 measures pressure in evaluation zone 90. Pressure monitoring device 54 includes any known pressure monitoring device that can measure and record transient pressure data and steady-state pressure data can be used. Examples of pressure gauges that can be used as pressure monitoring devices 54 include pressure recorders, such as pressure bombs and quartz gauges. Pressure monitoring device 54 is capable of capturing pressure data beginning at the moment shut-in valve 52 is closed in order to record the critical early transient pressure behavior. In at least one embodiment, pressure monitoring device 54 transmits pressure data in real-time to surface control system 70 through cable 22.

PLT 60 is a production logging tool (PLT) capable of measuring and characterizing flow. PLT 60 uses cable 22 of coiled tubing 20 to communicate to surface control system 70 in real time. In at least one embodiment, PLT 60 measures and records in real-time for assessment of evaluation zone 90. In at least one embodiment, PLT 60 includes a spinner and sensors to measure and characterize flow.

In some embodiments, the pressure data is recorded in memory. In at least one embodiment, the pressure data is stored in memory of pressure monitoring device 54. In at least one embodiment, the pressure data is stored in memory of PLT 60. Recording the data in memory acts as a data back-up. In some embodiments, the pressure data is transmitted to surface control system 70 at surface 100 in real time. In some embodiments, the pressure data is recorded in memory and transmitted to surface control system 70 in real time. In some embodiments, the data is transmitted via cable 22 in coiled tubing 20 to surface control system 70. In some embodiments, the pressure data is transmitted by wireless downhole gauges.

In one aspect, a method for performing a pressure buildup test is provided. The method is described with reference to FIGS. 1 and 1 a, however it is understood that the method could be performed with any of the embodiments or combinations of embodiments as described. The method includes the step of drilling well 80 for production of hydrocarbon fluids. Drilling well 80 also includes the step of casing well 80 with casing 82. The steps of drilling well 80 for production of hydrocarbon fluids and preparing well 80 by casing well 80 with casing 82 are standard procedures performed in the preparation of wells for production. Known methods can be used for drilling of well 80 for production and of casing well 80 with casing 82.

Casing 82 is perforated at evaluation zone 90. Perforating casing 82 and allowing flow provides the means to fully evaluate the production potential of a zone of interest. “Perforation” or “perforating” refers to a procedure to generate holes in the casing, thus allowing fluids, such as hydrocarbon fluids to flow from the reservoir into the interior of a well. The hydrocarbon fluid can be any fluid in a reservoir capable of being produced through well 80. Hydrocarbon fluids can include oil, natural gas, brine, water, and combinations thereof In at least one embodiment, the hydrocarbon fluid is oil. In at least one embodiment, the hydrocarbon fluid is natural gas. Evaluation zone 90 is at a predetermined depth of a zone of interest. In at least one embodiment, casing 82 is perforated at the predetermined depth of the zone of interest at the furthest distance from the surface.

Once casing 82 of well 80 is perforated at evaluation zone 90, pressure buildup test system 10 is deployed downhole in well 80, such that packer 40 is proximate to evaluation zone 90 by coiled tubing 20. As used, “proximate to evaluation zone” means the packer can be below the evaluation zone, alternately the packer can be in the midst of the evaluation zone, and alternately the packer can be above the evaluation zone. In at least one embodiment, pressure buildup test system 10 is deployed downhole in well 80 prior to casing 82 being perforated. In at least one embodiment, pressure buildup test system 10 is deployed downhole by wireline.

Once pressure buildup test system 10 is in position proximate to evaluation zone 90, the lift fluid is supplied via coiled tubing 20 and sub port 30 to lift the hydrostatic pressure of evaluation zone 90. Packer 40 is in retracted position, as shown in FIG. 1. Shut-in valve 52 is open. The hydrocarbon fluid in well 80 is lifted from evaluation zone 90 toward surface 100. Hydrocarbon fluid flow is measured real time via PLT 60. When the hydrocarbon fluid has been lifted from evaluation zone 90, a pressure buildup test can be performed. In at least one embodiment, the hydrocarbon fluid in well 90 is lifted toward the surface in the annulus, well space 84, between well 80 and coiled tubing 20, such that coiled tubing 20 supplies the lift fluid and is in the absence of hydrocarbon fluid.

To begin the pressure buildup test, packer 40 is placed in the set position, as shown in FIG. la, at the required depth of isolation at or near evaluation zone 90 to prevent wellbore storage effects from corrupting the well test data. After packer 40 is in the set position, the hydrocarbon fluid in evaluation zone 90 flows through shut-in valve 52 to sub port 30 and out to well space 84 and up to surface 100. The hydrocarbon fluid continues to flow until stable state is reached as indicated in surface control system 70 from readings transmitted by pressure monitoring device 54 and PLT 60. “Stable state” or “stable conditions” means a stable pressure and a stable flow rate through shut-in valve 52 as measured by pressure monitoring device 54 and PLT 60. As used throughout, “stable” means a steady-state or substantially steady-state in which the pressure or flow rate are constant and unchanging for a time period.

When stable state is reached shut-in valve 52 is shut, which begins the buildup of pressure for transient analysis. Shut-in valve 52 is closed and pressure measurements using pressure monitoring device 54 are recorded as pressure data. Pressure monitoring device 54 measures the pressure as it builds up in evaluation zone 90. In some embodiments, the pressure measurements begin during hydrocarbon fluid flow. In some embodiments, the pressure measurements begin at the moment shut-in valve 52 is closed. The pressure measurements are recorded over time to determine the pressure buildup rate. The pressure buildup rate is indicative of a well's production potential.

Shut-in valve 52 is closed quickly or suddenly, so that it closes in a small amount of time to record the instantaneous transient pressure data. Shut-in valve 52 is closed and the pressure monitoring device 54 records the pressure data for buildup analysis and measures the buildup pressure. As used herein, “pressure buildup” refers to the increase in the pressure values after the closure of the shut-in valve. The pressure buildup data are analyzed (for example, the pressure values, the derivate of the pressure values, and the second derivative of the pressure values) and characteristics of the formation can be inferred from the analyzed data set. Characteristics can include, for example, permeability, skin factor, and nearby faults. The duration of the pressure buildup test depends on characteristics the pressure buildup test data seeks to evaluate. For example, determination of faults at a distance from the wellbore requires more time than analysis of faults near the wellbore. There can be two ways to determine if the pressure buildup test is complete. In an instance where surface control system 70 is capable of real time monitoring of downhole conditions, then the real time surface readings can indicate the boundary of the test, in other words, surface control system can indicate when complete pressure buildup has been achieved. In an instance where surface control system 70 is not capable of real time monitoring of downhole conditions, then memory gauges can be used to collect the pressure data and the time can be estimated based on previous trials in the well and the reservoir. As a rule of thumb, the pressure buildup test can be expected to last 1.5 times the flow.

After the buildup test is complete, packer 40 is returned to the retracted position, such that packer 40 is unset or released, and pressure buildup test system 10 can be retrieved from within well 80. In at least one embodiment, after the buildup test is complete, packer 40 is returned to the retracted position and repositioned to another zone of interest in well 80 or another evaluation zone 90.

In some embodiments, the method further includes perforating casing 82 before performing the testing procedure. In some embodiments, multiple evaluation zones can be assessed without the need to remove the pressure buildup test system apparatus from well 80. In such embodiments, pressure buildup system 10 is positioned with packer 40 at a second evaluation zone and nitrogen is supplied via coiled tubing 20 to lift the hydrostatic pressure of the second evaluation zone and then pressure build test system 10 is used to measure an in-flow of hydrocarbons in a pressure buildup test. This can be repeated in any number of evaluation zones without removal of pressure buildup testing 10 from well 80.

In at least one embodiment, the casing is perforated in a first evaluation zone, the pressure buildup test system is lowered proximate the first evaluation zone and the pressure buildup test is completed. The pressure build up test system is then removed from the first evaluation zone and the first evaluation zone is then sealed off from connection with the well above the first evaluation zone. The first evaluation zone can be sealed by cementing or bridge block. At a second evaluation zone, at a predetermined depth that is closer to the surface than the first evaluation zone, the casing is again perforated. The pressure buildup test system is placed in the second evaluation zone and a second pressure buildup test is performed. This can be repeated in additional evaluation zones that progressively move closer to the surface. Perforating one evaluation zone at a time ensures that only the evaluation zone currently being evaluated contributes to the pressure data received by the pressure buildup system. It is understood that a high degree of accuracy is desired when conducting pressure buildup tests and small pressure perturbations can lead to well testing errors.

In further embodiments, well 80 is filled with a completion fluid. The completion fluid, or kill fluid, can be a fluid that can control the pressure of well 80. In some embodiments, brine is used as the completion fluid. Brine is salty water that has a higher density than fresh water. The brine can come from any source of brine that would be capable of controlling the pressure of well 80. In alternate embodiments, the kill fluid is a heavy fluid sufficient to stop the flow of hydrocarbons from the reservoir into well 80.

Benefits to the various embodiments disclosed in the present application include reducing the number of coiled tubing insertions for the purpose of evaluating unconventional and tight gas zones. Reducing the number of coiled tubing runs will also result in reducing the rigging up and down of coiled tubing surface equipment. Reductions in coiled tubing runs reduces the operational cost associated with such operations. Additionally, embodiments allow evaluation zones to be lifted and energized to flowing conditions by circulating nitrogen through coiled tubing to the evaluation zone. Various embodiments also allow for the evaluation and measurement of flow from the evaluation zone with production logging tools. PLT can be used to measure and characterize the well's production while it is flowing. PLT can be used to evaluate a zone during the lifting phase, prior to the pressure buildup test. Various embodiments further allow for performance of an instantaneous shut-in of the flowing zone to record a pressure buildup test using downhole pressure monitoring devices. Embodiments are in the absence of memory gauges or pre-set shut-in valves that close after a set time has lapsed. Various embodiments also allow for observation of pressure data in real-time via an electrical or fiber-optical data transmission cable to surface. Another benefit of embodiments is the ability to repeat the test method at multiple evaluation zones in a well without the need of retrieving coiled tubing to the surface.

In at least one embodiment, the downhole devices are in the absence of production tubing.

Although the methods and apparatus have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the inventive principle and scope. Accordingly, the scope should be determined by the following claims and their appropriate legal equivalents.

The singular forms “a”, “an” and “the” include plural referents, unless the context clearly dictates otherwise.

Optional or optionally means that the subsequently described event or circumstances may or may not occur. The description includes instances where the event or circumstance occurs and instances where it does not occur.

Ranges may be expressed here as from about one particular value to about another particular value. When such a range is expressed, it is to be understood that another embodiment is from the one particular value to the other particular value, along with all combinations within said range.

As used here and in the appended claims, the words “comprise,” “has,” and “include” and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps.

As used here, terms such as “first” and “second” are arbitrarily assigned and are merely intended to differentiate between two or more components of an apparatus. It is to be understood that the words “first” and “second” serve no other purpose and are not part of the name or description of the component, nor do they necessarily define a relative location or position of the component. Furthermore, it is to be understood that that the mere use of the term “first” and “second” does not require that there be any “third” component, although that possibility is contemplated under the scope. 

That which is claimed is:
 1. A method for performing a pressure buildup test in an evaluation zone of a well, the method comprising the steps of: perforating a casing of the well in the evaluation zone, wherein perforating the casing is operable to allow the flow of hydrocarbon fluids from the reservoir to the evaluation zone; deploying a pressure buildup test system into the evaluation zone of the well, the pressure buildup test system is configured to measure pressure in the evaluation zone, the pressure buildup test system comprises: a packer, the packer is configured to isolate the evaluation zone when in a set position and further is configured to create an annulus between the casing of the well and the pressure buildup test system in a retracted position; a sub port, the sub port configured to deliver a lift fluid to the evaluation zone; a coiled tubing, the coiled tubing configured to deliver the lift fluid from the surface to the sub port, wherein the pressure buildup test system is deployed by the coiled tubing, wherein the coiled tubing comprises a cable, the cable is configured to transmit electronic signals to a surface control system from the pressure buildup test system; a shut-in valve, the shut-in valve configured to control the flow of hydrocarbon fluids from the evaluation zone to a well space at a distance above the packer; a pressure monitoring device, the pressure monitoring device configured to measure pressure data in the evaluation zone and transmit the pressure data to the surface control system through the cable; and a PLT, the PLT configured to measure flow from the evaluation zone through the shut-in valve to the well space above the packer; supplying the lift fluid via the coiled tubing to lift the hydrostatic pressure of the evaluation zone, wherein lifting the hydrostatic pressure is operable to lift the hydrocarbon fluids in the evaluation zone through the between the packer and the casing toward the surface; moving the packer to the set position, wherein in the set position the packer contacts the casing of the well such that the hydrocarbon fluids in the evaluation zone flow through the shut-in valve to the well space; monitoring the pressure data of the evaluation zone to determine a stable state of the pressure data; closing the shut-in valve when the stable state of the pressure data is reached to prevent the flow of the hydrocarbon fluids from the evaluation zone; and measuring a buildup pressure in the evaluation zone using the pressure monitoring device.
 2. The method of claim 1, wherein the lift fluid is nitrogen.
 3. The method of claim 1, further comprising the step of returning the packer to the retracted position after the buildup pressure is measured.
 4. The method of claim 3, further comprising the steps of: re-positioning the pressure buildup test system to a second evaluation zone; moving the packer to the set position; monitoring the pressure data of the hydrocarbon fluids flowing through the shut-in valve to determine the stable state of the pressure data in the second evaluation zone; closing the shut-in valve when the stable state of the pressure data is reached to prevent the flow of the hydrocarbon fluids from the second evaluation zone; and measuring the buildup pressure in the second evaluation zone using the pressure monitoring device.
 5. The method of claim 1, further comprising the step of filling the well with a completion fluid.
 6. The method of claim 1, wherein the completion fluid is brine.
 7. The method of claim 1, wherein the coiled tubing comprises a valve, the valve configured to shut-off the flow of the lift fluid.
 8. The method of claim 1, further comprising the steps of: drilling the well for production of hydrocarbon fluids; and preparing the well by installing the casing in the well.
 9. An apparatus for pressure buildup testing in an evaluation zone of a well, the apparatus comprising: a packer, the packer is configured to isolate the evaluation zone when in a set position and is configured to create an annulus between a wall of the well and the apparatus in a retracted position; a sub port, the sub port configured to deliver a lift fluid to the evaluation zone; a coiled tubing, the coiled tubing configured to deliver the lift fluid from a surface to the sub port, wherein the apparatus is deployed by the coiled tubing, wherein the coiled tubing comprises a cable, the cable is configured to transmit electronic signals to a surface control system from the apparatus; a shut-in valve, the shut-in valve configured to control the flow of hydrocarbon fluids from the evaluation zone to a well space at a distance above the packer; a pressure monitoring device, the pressure monitoring device configured to measure pressure data in the evaluation zone and transmit the pressure data to the surface control system through the cable; and a PLT, the PLT configured to measure flow from the evaluation zone through the shut-in valve to the well space above the packer.
 10. The apparatus of claim 9, wherein the lift fluid is nitrogen.
 11. The apparatus of claim 9, wherein the coiled tubing comprises a valve, the valve configured to shut-off the flow of the lift fluid.
 12. The apparatus of claim 9, wherein the surface control system is configured to send and receive electronic signals to the shut-in valve.
 13. The apparatus of claim 9, wherein the surface control system is configured to send and receive electronic signals to the pressure monitoring device.
 14. The apparatus of claim 9, wherein the surface control system is configured to send and receive electronic signals to the PLT.
 15. The apparatus of claim 9, wherein the surface control system is configured to display the electronic signals transmitted by the cable and is further configured to store the electronic signals transmitted by the cable. 